Filtered smoking article

ABSTRACT

A filtered cigarette possesses a filter element incorporating activated carbon particles. A preferred filter element incorporates a filter material such as cellulose acetate tow, and that tow is plasticized using triacetin. A mixture of propylene glycol and triacetin is contacted with the activated carbon particles, and those particles so treated are incorporated into the filter element. Alternatively, a mixture of propylene glycol and triacetin is incorporated within the filter element, and a portion of that mixture is in contact with at least a portion of the activated carbon particles.

FIELD OF THE INVENTION

The present invention relates to tobacco products, such as smoking articles (e.g., cigarettes), and in particular, to filtered cigarettes.

BACKGROUND OF THE INVENTION

Popular smoking articles, such as cigarettes, have a substantially cylindrical rod shaped structure and include a charge, roll or column of smokable material, such as shredded tobacco (e.g., in cut filler form), surrounded by a paper wrapper, thereby forming a so-called “smokable rod” or “tobacco rod.” Normally, a cigarette has a cylindrical filter element aligned in an end-to-end relationship with the tobacco rod. Typically, a filter element comprises plasticized cellulose acetate tow circumscribed by a paper material known as “plug wrap.” Certain filter elements can incorporate polyhydric alcohols. See, for example, UK Pat. Spec. 755,475. Typically, the filter element is attached to one end of the tobacco rod using a circumscribing wrapping material known as “tipping paper.” It also has become desirable to perforate the tipping material and plug wrap, in order to provide dilution of drawn mainstream smoke with ambient air. Descriptions of cigarettes and the various components thereof are set forth in Tobacco Production, Chemistry and Technology, Davis et al. (Eds.) (1999). A cigarette is employed by a smoker by lighting one end thereof and burning the tobacco rod. The smoker then receives mainstream smoke into his/her mouth by drawing on the opposite end (e.g., the filter end) of the cigarette.

Certain cigarettes incorporate filter elements incorporating activated carbon or charcoal materials. For example, an exemplary cigarette filter can possess multiple segments, and at least one of those segments can comprise particles of high carbon-content materials. Various types of filters incorporating charcoal particles or activated carbon types of materials are set forth in U.S. Pat. Nos. 2,881,770 to Touey; 3,101,723 to Seligman et al.; 3,236,244 to Irby et al.; 3,311,519 to Touey et al.; 3,347,247 to Lloyd; 3,370,595 to Davis et al.; and 3,972,335 to Tigglebeck et al.; which are incorporated herein by reference.

It would be highly desirable to provide a cigarette possessing a filter element incorporating a carbonaceous material, such as particles of activated carbon; which filter element (i) incorporates a filter material and other filter component materials, and (ii) possesses the ability to efficiently remove effective amounts of various gas phase components of mainstream tobacco smoke passing through that filter element.

SUMMARY OF THE INVENTION

The present invention relates to a smoking article, and in particular, a rod shaped smoking article (e.g., a cigarette). The smoking article includes a lighting end (i.e., an upstream end) and a mouth end (i.e., a downstream end). A mouth end piece is located at the extreme mouth end of the smoking article, and the mouth end piece allows the smoking article to be placed in the mouth of the smoker to be drawn upon. The mouth end piece has the form of a filter element. The filter element incorporates an effective amount of a carbonaceous material, such as a charcoal or activated carbon type of material. The amount of carbonaceous material within the filter element is sufficient to alter gas phase components (e.g., reduce the levels of certain gas phase components) in the mainstream smoke passing through the filter element. At least a portion of the carbonaceous material within the filter element is in contact with an effective amount of a mixture of a polyol ester and a polyol. For example, at least a portion of the carbonaceous material within the filter element has applied thereto an effective amount of a liquid mixture of a glycerin ester (e.g., triacetin) and a low molecular weight polyol (e.g., glycerin or propylene glycol). The amount of polyol ester and polyol in intimate contact with the carbonaceous material is sufficient to minimize adverse effects of filter additives, such as triacetin, upon the ability of the carbonaceous material to remove certain gas phase components from the mainstream smoke passing through the filter element.

In one embodiment, the invention provides a cigarette comprising a filter, wherein the filter comprises a plasticized cellulose acetate tow and a carbonaceous material in particulate form, wherein the carbonaceous material is in contact with an intimate mixture of a polyol ester (e.g., a glycerin ester such as triacetin) and a polyol (e.g., a low molecular weight polyol such as glycerin or propylene glycol). The plasticizer of the plasticized cellulose acetate tow typically comprises triacetin. The cigarette will typically include a tobacco rod having smokable filler material contained within a circumscribing wrapping material, and the filter element will be connected to the tobacco rod at one end of the tobacco rod, the filter element incorporating filter material and having an end proximal to the tobacco rod and an end distal from the tobacco rod.

An exemplary carbonaceous material is in particulate form having a particle size of about 10 Mesh to about 400 Mesh, and present in an amount of between about 20 mg and about 500 mg. The weight ratio of polyol to polyol ester in the mixture can be, for example, between about 1:3 and about 25:1, more preferably between about 2:1 and about 10:1. In one embodiment, the polyol is present in an amount of between about 1 percent and about 25 percent based on the combined weight of the carbonaceous material and the polyol in the mixture, more preferably between about 7 percent and about 15 percent.

In another aspect, the present invention provides a method of improving gas phase filtration performance of a carbonaceous material in a smoking article, comprising treating the carbonaceous material with an intimate mixture of a polyol and a polyol ester.

BRIEF DESCRIPTION OF THE DRAWING

In order to assist the understanding of embodiments of the invention, reference will now be made to the appended drawing, which is not necessarily drawn to scale. The drawing is exemplary only, and should not be construed as limiting the invention.

FIG. 1 is a cross-sectional view of a smoking article having the form of a cigarette, showing the smokable material, the wrapping material components, and the filter element of the cigarette.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present inventions now will be described more fully hereinafter with reference to the accompanying drawing. The invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout. As used in this specification and the claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.

Referring to FIG. 1, there is shown a smoking article 10 in the form of a cigarette and possessing certain representative components of a smoking article of the present invention. The cigarette 10 includes a generally cylindrical rod 15 of a charge or roll of smokable filler material 16 contained in a circumscribing wrapping material 20. The rod 15 is conventionally referred to as a “tobacco rod.” The ends of the tobacco rod 15 are open to expose the smokable filler material. The cigarette 10 is shown as having one optional band 25 (e.g., a printed coating including a film-forming agent, such as starch, ethylcellulose, or sodium alginate) applied to the wrapping material 20, and that band circumscribes the cigarette rod in a direction transverse to the longitudinal axis of the cigarette. That is, the band 25 provides a cross-directional region relative to the longitudinal axis of the cigarette. The band 25 can be printed on the inner surface of the wrapping material (i.e., facing the smokable filler material), or less preferably, on the outer surface of the wrapping material. Although the cigarette can possess a wrapping material having one optional band, the cigarette also can possess wrapping material having further optional spaced bands numbering two, three, or more.

The wrapping material 20 of the tobacco rod 15 can have a wide range of compositions and properties. The selection of a particular wrapping material will be readily apparent to those skilled in the art of cigarette design and manufacture. Tobacco rods can have one layer of wrapping material; or tobacco rods can have more than one layer of circumscribing wrapping material, such as is the case for the so-called “double wrap” tobacco rods. Exemplary types of wrapping materials, wrapping material components and treated wrapping materials are described in U.S. Pat. No. 5,220,930 to Gentry; US Pat. Appl. 2004/0129281 to Hancock et al.; US Pat. Appl. 2005/0039764 to Barnes et al.; PCT WO 2004/057986 to Hancock et al.; and PCT WO 2004/047572 to Ashcraft et al.; which are incorporated herein by reference in their entireties.

At one end of the tobacco rod 15 is the lighting end 28, and at the other end is positioned a filter element 30. The filter element 30 positioned adjacent one end of the tobacco rod 15 such that the filter element and tobacco rod are axially aligned in an end-to-end relationship, preferably abutting one another. Filter element 30 may have a generally cylindrical shape, and the diameter thereof may be essentially equal to the diameter of the tobacco rod. The ends of the filter element 30 permit the passage of air and smoke therethrough.

The filter element 30 possesses a first filter segment 32 positioned adjacent one end of the tobacco rod 15. The first filter segment 32 includes filter material 40 (e.g., cellulose acetate tow impregnated with plasticizer, such as triacetin) that is over-wrapped along the longitudinally extending surface thereof with circumscribing plug wrap material 45. Within the filter material 40 of the first segment is dispersed a plurality of particles of carbonaceous material 50. At least a portion of the carbonaceous material 50, and typically virtually all of the carbonaceous material, is in intimate contact with an effective amount of a mixture of polyol ester (e.g., triacetin) and polyol (e.g., propylene glycol).

The filter element 30 possesses a second filter segment 55 longitudinally disposed relative to the first segment 32 and positioned at the extreme mouth end of the cigarette 10. The second filter segment 55 includes filter material 60 (e.g., cellulose acetate tow impregnated with plasticizer, such as triacetin) that is over-wrapped along the longitudinally extending surface thereof with circumscribing plug wrap material 65.

The filter element 30 is circumscribed along its outer circumference or longitudinal periphery by a layer of outer plug wrap 75. The outer plug wrap 75 overlies each of the first filter segment 32 and the second filter segment 55, so as to provide a combined, two segment filter element. The production of filter rods, filter segments and filter elements, and the manufacture of cigarettes from those filter rods, filter segments and filter elements can be carried out using the types of rod-forming units that have been employed to provide cigarette filters, multi-segment cigarette filters and filtered cigarettes. Multi-segment cigarette filter rods can be manufactured using a cigarette filter rod making device available under the brand name Mulfi from Hauni-Werke Korber & Co. KG of Hamburg, Germany. Other representative types of commercially available filter rod making equipment that can suitably modified for use include the KDF-2 unit available from Hauni-Werke Korber & Co. KG and the Decoufle unit available from Decoufle of France.

The filter element 30 is attached to the tobacco rod 15 using tipping material 88 (e.g., essentially air impermeable tipping paper), that circumscribes both the entire length of the filter element 30 and an adjacent region of the tobacco rod 15. The inner surface of the tipping material 88 is fixedly secured to the outer surface of the plug wrap 75 and the outer surface of the wrapping material 20 of the tobacco rod, using a suitable adhesive; and hence, the filter element and the tobacco rod are connected to one another.

A ventilated or air diluted smoking article can be provided with an optional air dilution means, such as a series of perforations 92, each of which extend through the tipping material and plug wrap. The optional perforations 92 can be made by various techniques known to those of ordinary skill in the art, such as laser perforation techniques. Alternatively, so-called off-line air dilution techniques can be used (e.g., through the use of porous paper plug wrap and pre-perforated tipping paper).

The dimensions of a representative cigarette 10 can vary. Preferred cigarettes are rod shaped, and can have diameters of about 7.5 mm (e.g., circumferences of about 20 mm to about 27 mm, often about 22.5 mm to about 25 mm); and can have total lengths of about 70 mm to about 120 mm, often about 80 mm to about 100 mm. The length of the filter element 30 can vary. Typical filter elements can have lengths of about 15 mm to about 40 mm, often about 20 mm to about 35 mm.

During use, the smoker lights the lighting end 28 of the cigarette 10 using a match or cigarette lighter. As such, the smokable material 16 begins to burn. The mouth end of the cigarette 10 is placed in the lips of the smoker. Thermal decomposition products (e.g., components of tobacco smoke) generated by the burning smokable material 16 are drawn through the cigarette 10, through the filter element 30, and into the mouth of the smoker. During draw, certain amount of certain gaseous components of the mainstream smoke are removed from the mainstream smoke by the particles of carbonaceous material 50 within the filter element 30. Carbonaceous filter components, such as activated charcoal particles, have the capability of capturing a wide range of mainstream tobacco smoke vapor phase components. The presence of certain commonly used components of filter elements (e.g., plasticizers, such as triacetin) can act to reduce the efficiency of the carbonaceous materials to remove vapor phase smoke components. However, the pretreatment of the carbonaceous material with a mixture of a polyol ester and a polyol acts to mitigate the adverse effects imparted by components such as triacetin.

Smokable materials and other associated materials useful for carrying out certain aspects of the present invention can vary. Smokable materials are materials that can be incorporated into the smokable segment or rod, and provide mass and bulk to some region within that smokable segment. Smokable materials undergo some type of destruction during conditions of normal use of the smoking article into which they are incorporated. Destruction of the smokable material, due at least in part to thermal decomposition of at least some component of that smokable material, results in the formation of an aerosol having the form normally characterized as “smoke.” For example, smokable materials incorporating tobacco materials are intended to burn, or otherwise undergo thermal decomposition, to yield tobacco smoke. The selection of tobacco types and tobacco blends can determine the chemical composition of, and the sensory and organoleptic characteristics of, that aerosol produced when that tobacco material or blend of tobacco materials is burned.

It is most highly preferred that smokable materials of the smokable segment incorporate tobacco of some form. Preferred smokable materials are composed predominantly of tobacco of some form, based on the dry weights of those materials. That is, the majority of the dry weight of those materials, and the majority of the weight of a mixture incorporating those materials (including a blend of materials, or materials having additives applied thereto or otherwise incorporated therein) can be provided by tobacco of some form. For example, those materials can be processed tobaccos that incorporate minor amounts non-tobacco filler materials (e.g., calcium carbonate particles, carbonaceous materials, grains or wood pulp) and/or binding agents (e.g., guar gum, sodium alginate or ammonium alginate); and/or a blend of those materials can incorporate tobacco substitutes or extenders. Those materials, and blends incorporating those materials, frequently are composed of greater than about 70 percent tobacco, often are greater than about 80 percent tobacco, and generally are greater than about 90 percent tobacco, on a dry weight basis, based on the combined weights of the tobacco, non-tobacco filler material, and non-tobacco substitute or extender. Those materials also can be composed of virtually all tobacco material, and not incorporate any non-tobacco fillers, substitutes or extenders.

The smokable material can be treated with tobacco additives of the type that are traditionally used for the manufacture of cigarettes, such as casing and/or top dressing components. See, for example, U.S. Pat. Nos. 3,419,015 to Wochnowski; 4,054,145 to Berndt et al.; 4,887,619 to Burcham, Jr. et al.; 5,022,416 to Watson; 5,103,842 to Strang et al.; and 5,711,320 to Martin. Typical casing materials include water, sugars and syrups (e.g., sucrose, glucose and high fructose corn syrup), humectants (e.g. glycerin or propylene glycol), and flavoring agents (e.g., cocoa and licorice). Those added components also include top dressing materials (e.g., flavoring materials, such as menthol). See, for example, U.S. Pat. No. 4,449,541 to Mays et al. Additives also can be added to the smokable materials using the types of equipment described in U.S. Pat. No. 4,995,405 to Lettau, or that are available as Menthol Application System MAS from Kohl Maschinenbau GmbH. The selection of particular casing and top dressing components is dependent upon factors such as the sensory characteristics that are desired, and the selection and use of those components will be readily apparent to those skilled in the art of cigarette design and manufacture. See, Gutcho, Tobacco Flavoring Substances and Methods, Noyes Data Corp. (1972) and Leffingwell et al., Tobacco Flavoring for Smoking Products (1972).

Smokable materials typically are used in forms, and in manners, that are traditional for the manufacture of smoking articles, such as cigarettes. Those materials can incorporate shredded pieces of tobacco (e.g., as lamina and/or stem), and/or those materials can be tobacco materials that are in processed forms. For example, those materials normally are used in cut filler form (e.g., shreds or strands of tobacco filler cut into widths of about 1/10 inch to about 1/60 inch, preferably about 1/20 inch to about 1/35 inch, and in lengths of about ⅛ inch to about 3 inches, usually about ¼ inch to about 1 inch). Alternatively, though less preferred, those materials, such as processed tobacco materials, can be employed as longitudinally extending strands or as sheets formed into the desired configuration, or as compressed or extruded pieces formed into a desired shape.

Tobacco materials can include, or can be derived from, various types of tobaccos, such as flue-cured tobacco, burley tobacco, Oriental tobacco or Maryland tobacco, dark tobacco, dark-fired tobacco and Rustica tobaccos, as well as other rare or specialty tobaccos, or blends thereof. Descriptions of various types of tobaccos, growing practices, harvesting practices and curing practices are set for in Tobacco Production, Chemistry and Technology, Davis et al. (Eds.) (1999). See, also, US Pat. Application 2004/0084056 to Lawson et al. Most preferably, the tobacco materials are those that have been appropriately cured and aged.

Typically, tobacco materials are used in a so-called “blended” form. For example, certain popular tobacco blends, commonly referred to as “American blends,” comprise mixtures of flue-cured tobacco, burley tobacco and Oriental tobacco. Such blends, in many cases, contain tobacco materials that have processed forms, such as processed tobacco stems (e.g., cut-rolled stems, cut-rolled-expanded stems or cut-puffed stems), volume expanded tobacco (e.g., puffed tobacco, such as dry ice expanded tobacco (DIET), preferably in cut filler form). Tobacco materials also can have the form of reconstituted tobaccos (e.g., reconstituted tobaccos manufactured using paper-making type or cast sheet type processes). Tobacco reconstitution processes traditionally convert portions of tobacco that normally might be wasted into commercially useful forms. For example, tobacco stems, recyclable pieces of tobacco and tobacco dust can be used to manufacture processed reconstituted tobaccos of fairly uniform consistency. The precise amount of each type of tobacco within a tobacco blend used for the manufacture of a particular cigarette brand can vary, is a manner of design choice, depending upon factors such as the sensory characteristics desired. See, for example, Tobacco Encyclopedia, Voges (Ed.) p. 44-45 (1984), Browne, The Design of Cigarettes, 3^(rd) Ed., p. 43 (1990) and Tobacco Production, Chemistry and Technology, Davis et al. (Eds.) p. 346 (1999). Various representative tobacco types, processed types of tobaccos, types of tobacco blends, cigarette components and ingredients, and tobacco rod configurations, also are set forth in U.S. Pat. Nos. 4,836,224 to Lawson et al.; 4,924,883 to Perfetti et al.; 4,924,888 to Perfetti et al.; 5,056,537 to Brown et al.; 5,159,942 to Brinkley et al.; 5,220,930 to Gentry; 5,360,023 to Blakley et al.; 5,714,844 to Young et al.; and 6,730,832 to Dominguez et al.; US Pat. Applications 2002/0000235 to Shafer et al.; 2003/0075193 to Li et al.; and 2003/0131859 to Li et al.; PCT WO 02/37990 to Bereman; US Pat. Application 2004/0084056 to Lawson et al.; US Pat. Application 2004/0255965 to Perfetti et al.; US Pat. Application 2005/0066984 to Crooks et al.; US Pat. Application 2005/0066986 to Nestor et al.; and Bombick et al., Fund. Appl. Toxicol., 39, p. 11-17 (1997); which are incorporated herein by reference.

The wrapping materials can vary. The tobacco rod can possess one layer of wrapping material or more than one layer of circumscribing wrapping material, such as is the case for the so-called “double wrap” tobacco rods. Exemplary types of wrapping materials, wrapping material components and treated wrapping materials are described in U.S. Pat. Nos. 5,105,838 to White et al.; 5,271,419 to Arzonico et al.; 5,220,930 to Gentry and 6,874,508 to Shafer et al.; PCT WO 01/08514 to Fournier et al.; PCT WO 03/043450 to Hajaligol et al.; US Pat. Application 2003/0114298 to Woodhead et al.; 2004/0134631 to Crooks et al.; 2005/0005947 to Hampl, Jr. et al.; 2005/0005947 to Hampl, Jr. et al.; 2005/0016556 to Ashcraft et al.; and 2005/0076929 to Fitzgerald et al.; and PCT WO 2005/039326 to Rasouli et al.; which are incorporated herein by reference in their entireties. Representative wrapping materials are commercially available as R. J. Reynolds Tobacco Company Grades 119, 170, 419, 453, 454, 456, 465, 466, 490, 525, 535, 557, 652, 664, 672, 676 and 680 from Schweitzer-Maudit International. Colored wrapping materials (e.g., brown colored papers) can be employed. Reconstituted tobacco materials also can be used, particularly as inner wrapping materials (e.g., in regions that are overwrapped with at least one further layer of wrapping material), and representative reconstituted tobacco materials useful as wrapping materials for smokable rods are set forth in U.S. Pat. Nos. 5,074,321 to Gentry et al.; 5,159,944 to Arzonico et al.; 5,261,425 to Raker; 5,462,073 to Bowen; and 5,699,812 to Bowen; which are incorporated herein by reference.

The filter element incorporates carbonaceous material. A carbonaceous material is a material that is composed primarily of carbon, and preferred carbonaceous materials are composed of virtually all carbon. Typically carbonaceous materials comprise carbon in amounts of more than about 85 percent, generally more than about 90 percent, often more than about 95 percent, and frequently more than about 98 percent, by weight. The carbonaceous material can have the form of charcoal, but most preferably is an activated carbon material. Activated carbon materials are high surface area materials. Exemplary activated carbon materials have surface areas of more than about 200 m²/g, often more than about 1000 m²/g, and frequently more than about 1500 m²/g, as determined using the Brunaver, Emmet and Teller (BET) method described in J. Amer. Chem. Soc., Vol. 60(2), pp. 309-319 (1938).

The carbonaceous materials can be derived from synthetic or natural sources. Materials such as rayon or nylon can be carbonized, followed by treatment with oxygen to provide activated carbonaceous materials. Materials such as wood and coconut shells can be carbonized, followed by treatment with oxygen to provide activated carbonaceous materials. Exemplary carbonaceous materials are coconut shell types of activated carbons available from sources such as Calgon Carbon Corporation, Gowrishankar Chemicals, Carbon Activated Corp. and General Carbon Corp. See, also, for example, Activated Carbon Compendium, Marsh (Ed.) (2001), which is incorporated herein by reference.

Various types of charcoals and activated carbon materials suitable for incorporation into cigarette filters, various other filter element component materials, various types of cigarette filter element configurations and formats, and various manners and methods for incorporating carbonaceous materials into cigarette filter elements, are set forth in U.S. Pat. Nos. 3,217,715 to Berger et al.; 3,648,711 to Berger et al.; 3,957,563 to Sexstone; 4,174,720 to Hall; 4,201,234 to Neukomm; 4,223,597 to Lebert; 5,137,034 to Perfetti et al.; 5,360,023 to Blakley et al.; 5,568,819 to Gentry et al.; 5,622,190 to Arterbery et al.; 6,537,186 to Veluz; 6,584,979 to Xue et al.; 6,761,174 to Jupe et al.; and 6,789,547 to Paine III; US Pat. Appl. Nos. 2002/0166563 to Jupe et al.; 2002/0020420 to Xue et al.; 2003/0200973 to Xue et al.; 2003/0154993 to Paine et al.; 2003/0168070 to Xue et al.; 2004/0194792 to Zhuang et al.; 2004/0226569 to Yang et al.; 2004/0237984 to Figlar et al.; 2005/0133051 to Luan et al.; 2005/0049128 to Buhl et al.; and 2005/0066984 to Crooks et al.; and European Pat. Appl. 579410 to White; and PCT WO 02/37990 to Bereman; which are incorporated herein by reference. Representative types of cigarettes possessing filter elements incorporating carbonaceous materials have been available as “Benson & Hedges Multifilter” by Philip Morris Inc., in the State of Florida during 2005 as a Philip Morris Inc. test market brand known as “Malboro Ultra Smooth,” and as “Mild Seven” by Japan Tobacco Inc. As such, the carbonaceous material can be incorporated within a filter element by incorporating that carbonaceous material within paper or other sheet-like material (e.g., as a longitudinally disposed segment of gathered, shredded, or otherwise configured paper-like material), within a segment of a cavity filter (e.g., a particles or granules within the central cavity region of a three segment or stage filter element), or dispersed within a filter material (e.g., as particles or granules dispersed throughout a filter tow or gathered non-woven web material) as a segment of a longitudinally multi-segmented filter element.

The carbonaceous material is incorporated into, and configured within, the filter element. A typical cigarette filter element of the present invention possesses carbonaceous material within at least one component or segment of the filter element in a manner such that components of at least a portion of the filter element (e.g., filter additives, such as triacetin) can have the ability to come into contact with, and adversely affect the mainstream smoke gas phase removal efficiency of, carbonaceous material within the filter element.

Other component segments of the filter element can vary. Representative filter element segments can incorporate the types of filter element components, designs and formats set forth in Browne, The Design of Cigarettes, 3^(rd) Ed. (1990); Tobacco Production, Chemistry and Technology, Davis et al. (Eds.) 1999; U.S. Pat. Nos. 4,508,525 to Berger; 4,807,809 to Pryor et al.; 4,903,714 to Barnes et al.; 4,920,990 to Lawrence et al.; 5,012,829 to Thesing et al.; 5,025,814 to Raker; 5,074,320 to Jones, Jr. et al.; 5,076,295 to Saintsing et al.; 5,101,839 to Jakob et al.; 5,105,834 to Saintsing et al.; 5,105,838 to White et al.; 5,271,419 to Arzonico et al.; 5,137,034 to Perfetti et al.; 5,396,909 to Gentry et al.; 5,595,218 to Koller et al.; 5,718,250 to Banerjee et al.; 6,530,377 to Lesser et al.; 6,615,842 to Cerami et al.; 6,631,722 to MacAdam et al.; and 6,792,953 to Lesser et al.; US Pat. Applications 2002/0014453 to Lilly, Jr. et al.; 2004/0261807 to Dube et al.; and 2005/0133052 to Fournier et al.; U.S. patent application Ser. Nos. 10/901,662, filed Jul. 29, 2004, to Gonterman et al.; which are incorporated herein by reference. Representative filter materials can be manufactured from tow materials (e.g., cellulose acetate or polypropylene tow) or gathered web materials (e.g., gathered webs of paper, reconstituted tobacco, cellulose acetate, polypropylene or polyester).

The filter element incorporates an effective amount of a carbonaceous material, and particularly an effective amount of activated carbon. The effective amount is an amount that, when incorporated into the filter element, provides some desired degree of alteration of the mainstream smoke of a cigarette incorporating that filter element. For example, a cigarette filter element incorporating activated carbon particles or granules can act to lower the yield of certain gas phase components of the mainstream smoke passing through that filter element. Typically, the amount of carbonaceous material within the filter element is at least about 20 mg, often at least about 30 mg, and frequently at least about 40 mg, on a dry weight basis. Typically, the amount of carbonaceous material within the filter element does not exceed about 500 mg, generally does not exceed about 400 mg, often does not exceed about 300 mg, and frequently does not exceed about 200 mg, on a dry weight basis.

The carbonaceous material of the filter element is employed in a suitable form. For example, the carbonaceous material can have a form that can be characterized as powdered, granular, particulate form, or the like. Typical particle sizes are greater than about 10 Mesh, often greater than about 20 Mesh, and frequently greater than about 30 Mesh. Typical particle sizes are less than about 400 Mesh, often less than about 300 Mesh, and frequently less than about 200 Mesh.

At least a portion of the carbonaceous material within the filter element is in intimate contact with an effective amount of a mixture of a polyol ester and a polyol. That is, an effective amount of the liquid component mixture is applied to the carbonaceous material, most preferably in order that a significant amount the surface region of the carbonaceous material is contacted with the mixture. Preferably, virtually the entire surface region of the carbonaceous material within the filter element has been exposed to the mixture so as to have the ability to be in intimate contact with that mixture; and most preferably, all of the carbonaceous material within the filter element is in intimate contact with that mixture. For example, at least a portion of the carbonaceous material with the filter element is in intimate contact with an effective amount of a mixture of a glycerin ester. A representative glycerin ester is triacetin. A preferred polyol is a low molecular weight polyol (e.g., a polyol having a molecular weight of less than about 200 Da, and most preferably less than about 100 Da). Exemplary polyols are glycerin and propylene glycol.

Prior to use of the cigarette, at least a portion of the activated carbon within the filter element of that cigarette is treated with an intimate admixture of liquid components. That is, the liquid components can be applied to the activated carbon prior to incorporation within the filter element. Most preferably, the liquid admixture is a well mixed solution of miscible liquid components. Most preferably, the admixture of liquid components is sprayed onto the carbonaceous material. For example, the liquid admixture can be sprayed onto carbonaceous material that is positioned on a moving conveyor belt or within a rotating pill coating drum. Alternatively, the carbonaceous material can be contacted with the liquid admixture within a fluidized bed, or other suitable device for contacting liquid components with a particulate or granular solid material. The carbonaceous material so treated then can be incorporated into the filter element or filter element component. If desired, the liquid components can be applied to the carbonaceous material that has been incorporated within a filter element or filter element component. For example, a filter element component that incorporate carbonaceous material can be subjected to injection, or other appropriate application, of liquid admixture in order that a desired amount of that liquid admixture is applied to the carbonaceous material within that filter element component. As a result, the admixture of liquid components so contacted with the carbonaceous material can act in a manner so as to moderate, reduce, limit or minimize the adverse effects of certain filter element components upon the ability of those carbonaceous materials within those filter elements to remove certain gas phase components from mainstream cigarette smoke drawn through those filter elements.

The relative amount of polyol and relative amount of polyol ester that are contacted with the carbonaceous material can vary. The relative amounts of polyol and polyol ester are sufficient to provide for reduction or minimization of the adverse effects of filter element additives, such as triacetin, upon the ability of carbonaceous materials within those filter elements to remove certain gas phase components from mainstream cigarette smoke drawn through those filter elements. Most preferably, the amount of polyol that is employed is greater than the amount of the polyol ester that is employed, on a weight basis. Exemplary ratios of polyol to polyol ester typically are less than about 25:1, generally are less than about 20:1, often are less than about 15:1, an frequently are less than about 10:1, on a weight basis. Exemplary ratios of polyol to polyol ester typically are at least about 1:3, generally are at least about 1:2, often are at least about 1:1, an frequently are at least about 2:1, on a weight basis.

The amount of the mixture of polyol and polyol ester that is in intimate contact with the carbonaceous material can vary. The amounts of polyol and polyol ester additive relative to carbonaceous material are sufficient to provide for reduction or minimization of the adverse effects of filter element additives, such as triacetin, upon the ability of carbonaceous materials within those filter elements to remove certain gas phase components from mainstream cigarette smoke drawn through those filter elements. Typical amounts of mixture that are applied to the carbonaceous material are such that polyol content of the treated carbonaceous material is at least about 1 percent, generally at least about 3 percent, often at least about 5 percent, and frequently at least about 7 percent, of the combined weight of the carbonaceous material and polyol, on a dry weight basis. Typical amounts of mixture that are applied to the carbonaceous material are such that polyol content of the treated carbonaceous material is less than about 25 percent, often less than about 20 percent, and frequently less than about 15 percent, of the combined weight of the carbonaceous material and polyol, on a dry weight basis.

The moisture content of the carbonaceous material can vary. Typically, the moisture content of the carbonaceous material within the filter element, prior to use of the cigarette incorporating that filter element, is less than about 30 percent, often less than about 25 percent, and frequently less than about 20 percent, based on the combined weight of the carbonaceous material and moisture. Typically, the moisture content of the carbonaceous material within the filter element, prior to use of the cigarette incorporating that filter element, is greater than about 3 percent, often greater than about 5 percent, and greater less than about 8 percent, based on the combined weight of the carbonaceous material and moisture.

The plug wrap can vary. See, for example, U.S. Pat. No. 4,174,719 to Martin. Typically, the plug wrap is a porous or non-porous paper material. Plug wrap materials are commercially available. Exemplary porous plug wrap papers are available from Schweitzer-Maudit International as Porowrap Plug Wrap 17-M1, 33-M1, 45-M1, 65-M9, 95-M9, 150-M4, 260-M4 and 260-M4T. Non-porous plug wraps exhibit porosities of less than about 10 CORESTA units, and preferably less than about 5 CORESTA units. Exemplary non-porous plug wrap papers are available as Ref. No. 646 Grade from Olsany Facility (OP Paprina) of the Czech Republic (Trierenberg Holding). Plug wrap paper can be coated, particularly on the surface that faces the filter material, with a layer of a film-forming material. Such a coating can be provided using a suitable polymeric film-forming agent (e.g., ethylcellulose, ethylcellulose mixed with calcium carbonate, or a so-called lip release coating composition of the type commonly employed for cigarette manufacture). Alternatively, a plastic film (e.g., a polypropylene film) can be used as a plug wrap material. For example, non-porous polypropylene materials that are available as ZNA-20 and ZNA-25 from Treofan Germany GmbH & Co. KG can be employed as plug wrap materials.

For cigarettes of the present invention that are air diluted or ventilated, the amount or degree of air dilution or ventilation can vary. Frequently, the amount of air dilution for an air diluted cigarette is greater than about 10 percent, generally is greater than about 20 percent, often is greater than about 30 percent, and sometimes is greater than about 40 percent. Typically, the upper level for air dilution for an air diluted cigarette is less than about 80 percent, and often is less than about 70 percent. As used herein, the term “air dilution” is the ratio (expressed as a percentage) of the volume of air drawn through the air dilution means to the total volume and air and aerosol drawn through the cigarette and exiting the extreme mouth end portion of the cigarette. Higher air dilution levels can act to reduce the transfer efficiency of aerosol forming material into mainstream aerosol.

Preferred cigarettes of the present invention exhibit desirable resistance to draw. For example, an exemplary cigarette exhibits a pressure drop of between about 50 and about 200 mm water pressure drop at 17.5 cc/sec. air flow. Preferred cigarettes exhibit pressure drop values of between about 60 mm and about 180, more preferably between about 70 mm to about 150 mm, water pressure drop at 17.5 cc/sec. air flow. Typically, pressure drop values of cigarettes are measured using a Filtrona Cigarette Test Station (CTS Series) available form Filtrona Instruments and Automation Ltd.

Cigarettes of the present invention, when smoked, yield an acceptable number of puffs. Such cigarettes normally provide more than about 6 puffs, and generally more than about 8 puffs, per cigarette, when machine smoked under FTC smoking conditions. Such cigarettes normally provide less than about 15 puffs, and generally less than about 12 puffs, per cigarette, when smoked under FTC smoking conditions. FTC smoking conditions consist of 35 ml puffs of 2 second duration separated by 58 seconds of smolder.

Cigarettes of the present invention, when smoked, yield mainstream aerosol. The amount of mainstream aerosol that is yielded per cigarette can vary. When smoked under FTC smoking conditions, an exemplary cigarette yields an amount of FTC “tar” that normally is at least about 1 mg, often is at least about 3 mg, and frequently is at least about 5 mg. When smoked under FTC smoking conditions, an exemplary cigarette yields an amount of FTC “tar” that normally does not exceed about 20 mg, often does not exceed about 15 mg, and frequently does not exceed about 12 mg.

Filter elements of the present invention can be incorporated within the types of cigarettes set forth in U.S. Pat. Nos. 4,756,318 to Clearman et al.; 4,714,082 to Banerjee et al.; 4,771,795 to White et al.; 4,793,365 to Sensabaugh et al.; 4,989,619 to Clearman et al.; 4,917,128 to Clearman et al.; 4,961,438 to Korte; 4,966,171 to Serrano et al.; 4,969,476 to Bale et al.; 4,991,606 to Serrano et al.; 5,020,548 to Farrier et al.; 5,027,836 to Shannon et al.; 5,033,483 to Clearman et al.; 5,040,551 to Schlatter et al.; 5,050,621 to Creighton et al.; 5,052,413 to Baker et al.; 5,065,776 to Lawson; 5,076,296 to Nystrom et al.; 5,076,297 to Farrier et al.; 5,099,861 to Clearman et al.; 5,105,835 to Drewett et al.; 5,105,837 to Barnes et al.; 5,115,820 to Hauser et al.; 5,148,821 to Best et al.; 5,159,940 to Hayward et al.; 5,178,167 to Riggs et al.; 5,183,062 to Clearman et al.; 5,211,684 to Shannon et al.; 5,240,014 to Deevi et al.; 5,240,016 to Nichols et al.; 5,345,955 to Clearman et al.; 5,396,911 to Casey, III et al.; 5,551,451 to Riggs et al.; 5,595,577 to Bensalem et al.; 5,727,571 to Meiring et al.; 5,819,751 to Barnes et al.; 6,089,857 to Matsuura et al.; 6,095,152 to Beven et al; and 6,578,584 Beven; which are incorporated herein by reference. For example, filter elements of the present invention can be incorporated within the types of cigarettes that have been commercially marketed under the brand names “Premier” and “Eclipse” by R. J. Reynolds Tobacco Company. See, for example, those types of cigarettes described in Chemical and Biological Studies on New Cigarette Prototypes that Heat Instead of Burn Tobacco, R. J. Reynolds Tobacco Company Monograph (1988) and Inhalation Toxicology, 12:5, p. 1-58 (2000); which are incorporated herein by reference.

EXPERIMENTAL

The following example is provided to illustrate embodiments of the present invention, and should not be considered to limit the scope thereof. Unless otherwise noted, all parts and percentages are by weight.

Activated charcoal particles of the type used for the manufacture of conventional “dalmation” filter segments of charcoal filter cigarettes are provided. The moisture content of the activated charcoal particles is about 15 percent. Activated charcoal samples fortified with propylene glycol, triacetin, or a mixture thereof, are prepared by adding a pre-determined amount of charcoal to a rotating mini-pill coating machine. The opening of the pill drum is covered with aluminum foil, and a small hole is formed in the center region of the aluminum foil. The pill drum is operated at moderate rotation. An air aspirator is inserted through the hole in the aluminum foil, and the other end of the aspirator is inserted into a container containing a liquid that is selected from the following: (i) a mixture of propylene glycol and triacetin, (ii) propylene glycol, or (iii) triacetin. After complete fluid aspiration, the drum is rotated for an additional five minutes, to facilitate condensation of the resulting aerosol of liquid onto the charcoal particles. As such, the liquid can be provided in intimate contact with the charcoal particles.

Tobacco burning cigarette cigarettes, each having a length of about 84 mm (tobacco rod length of about 57 mm and triacetin-plasticized cellulose acetate filter length of about 27 mm), are fitted into Cambridge filter pad holders. That filter pad holder does not possess a filter pad. To the other end of the filter pad holder is affixed, using Tygon® type of tubing, a glass cylinder containing a pre-determined mass of charcoal, dispersed over a known bed length. The glass cylinder is constructed by filing off the drawn out end of a capillary pipette providing a glass cylinder of approximately 75 mm in length, and approximately the same diameter as a cigarette. Either charcoal (for packing of 125 mg charcoal at a sample length of 10 mm), or a mixture of one part charcoal to 10 parts semolina (for packing of 25 mg charcoal at a sample length of 20 mm), is loosely packed in the cylinder, and quartz wool is used to pack each end of the sample within the cylinder. To the other end of that glass cylinder is affixed a second Cambridge filter pad holder having a Cambridge filter pad installed. This second filter pad holder is attached to a conventional smoking machine using Tygon® type tubing. Thus, as the cigarette rod is smoked, smoke is passed through the first filter holder, through the charcoal bed, through the second filter holder, and through the smoking machine.

Each cigarette is machine smoked to a butt length of 35 mm. Smoking conditions consist of 45 ml puffs, each of 2 second duration, taking every 40 seconds. Each cigarette yields about 8 to about 10 puffs, on average. For each cigarette, a consistent number of puffs are taken.

The instrumentation and techniques used to identify gas phase components collected under the foregoing smoking conditions are essentially of the type set forth by Gordon, et al., 57^(th) Tobacco Science Research Conference, Vol. 57, Paper No. 63 (Sep. 21-24, 2003).

A cigarette of the present invention that is smoked through a bed of charcoal treated with 10 percent mixture of about 6 parts propylene glycol and about 1 part triacetin, and configured in a 25 mg charcoal/20 mm arrangement within the glass cylinder, yields about 1678 total ion current area counts, while a similar cigarette smoked through a bed of similarly treated charcoal configured in a 125 mg charcoal/10 mm arrangement within the glass cylinder yields about 184 total counts. For that cigarette, the sample smoked through the treated charcoal configured in the 25 mg/20 mm arrangement yields acetaldehyde ion current area counts of about 279, benzene counts of about 17, and acetone counts of about 160. For that cigarette, the sample smoked through the treated charcoal configured in the 125 mg/10 mm arrangement yields acetaldehyde ion current area counts of about 24, benzene counts of about 0.1, and acetone counts of about 1.6.

A comparison cigarette that is smoked through a bed of untreated charcoal that is configured in a 25 mg/20 mm arrangement within the glass cylinder yields about 1924 total ion current area counts, while a similar cigarette smoked through a bed of untreated charcoal configured in a 125 mg/10 mm arrangement within the glass cylinder yields about 128 total counts. For that comparison cigarette, the sample smoked through the untreated charcoal configured in the 25 mg/20 mm arrangement yields acetaldehyde ion current area counts of about 272, benzene counts of about 27, and acetone counts of about 153. For that cigarette, the sample smoked through the untreated charcoal configured in the 125 mg/10 mm arrangement yields acetaldehyde ion current area counts of about 2.9, benzene counts of non-detect, and acetone counts of non-detect.

A comparison cigarette that is smoked through a bed of charcoal treated with 10 percent propylene glycol, and configured in a 25 mg charcoal/20 mm arrangement within the glass cylinder, yields about 2493 total ion current area counts, while a similar cigarette smoked through a bed of similarly treated charcoal configured in a 125 mg charcoal/10 mm arrangement within the glass cylinder yields about 421 total counts. For that cigarette, the sample smoked through the treated charcoal configured in the 25 mg/20 mm arrangement yields acetaldehyde ion current area counts of about 360, benzene counts of about 30, and acetone counts of about 220. For that cigarette, the sample smoked through the treated charcoal configured in the 125 mg/10 mm arrangement yields acetaldehyde ion current area counts of about 61, benzene counts of non-detect, and acetone counts of about 1.1.

A comparison cigarette that is smoked through a bed of charcoal treated with 5 percent triacetin, and configured in a 25 mg charcoal/20 mm arrangement within the glass cylinder, yields about 2914 ion current area counts, while a similar cigarette smoked through a bed of similarly treated charcoal configured in a 125 mg charcoal/10 mm arrangement within the glass cylinder yields about 403 total counts. For that cigarette, the sample smoked through the treated charcoal configured in the 25 mg/20 mm arrangement yields acetaldehyde ion current area counts of about 330, benzene counts of about 52, and acetone counts of about 307. For that cigarette, the sample smoked through the treated charcoal configured in the 125 mg/10 mm arrangement yields acetaldehyde ion current area counts of about 73, benzene counts of about 1.1, and acetone counts of about 12.

The data show that either of propylene glycol or triacetin when contacted with activated charcoal, act to reduce the propensity or ability of activated charcoal to remove gas phase components of mainstream cigarette smoke. However, the data also show that an admixture of propylene glycol and triacetin, when applied to activated charcoal, does not adversely affect, to any significant degree, the ability of activated charcoal to remove gas phase components of mainstream cigarette smoke.

Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawing. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. 

1. A cigarette comprising: (a) a tobacco rod having a smokable filler material contained within a circumscribing wrapping material; (b) a filter element connected to the tobacco rod at one end of the tobacco rod, said filter element incorporating filter material and having an end proximal to the tobacco rod and an end distal from the tobacco rod; (c) a carbonaceous material incorporated within the filter element; and (d) an intimate mixture of a polyol ester and a polyol incorporated within the filter element, at least a portion thereof in contact with the carbonaceous material.
 2. A cigarette comprising: (a) a tobacco rod having a smokable filler material contained within a circumscribing wrapping material; (b) a filter element connected to the tobacco rod at one end of the tobacco rod, said filter element incorporating filter material and having an end proximal to the tobacco rod and an end distal from the tobacco rod; (c) a carbonaceous material incorporated within the filter element; and (d) an intimate mixture of a polyol ester and a polyol in contact with at least a portion of the carbonaceous material.
 3. The cigarette of claim 1, wherein the intimate mixture includes triacetin and propylene glycol.
 4. The cigarette of claim 1, wherein the carbonaceous material is disposed within the filter element in a region composed of cellulose acetate tow plasticized using triacetin.
 5. The cigarette of claim 1, wherein the carbonaceous material comprises activated carbon particles incorporated within the filter element in a region composed of cellulose acetate tow plasticized using triacetin, and the cellulose acetate tow is circumscribed on its longitudinal periphery by plug wrap.
 6. The cigarette of claim 2, wherein the intimate mixture includes triacetin and propylene glycol.
 7. The cigarette of claim 2, wherein the carbonaceous material is disposed within the filter element in a region composed of cellulose acetate tow plasticized using triacetin.
 8. The cigarette of claim 2, wherein the carbonaceous material comprises activated carbon particles incorporated within the filter element in a region composed of cellulose acetate tow plasticized using triacetin, and the cellulose acetate tow is circumscribed on its longitudinal periphery by plug wrap.
 9. The cigarette of claim 1, wherein the carbonaceous material is in particulate form having a particle size between about 10 Mesh and about 400 Mesh, and wherein the carbonaceous material is present in an amount of between about 20 mg and about 500 mg.
 10. The cigarette of claim 2, wherein the carbonaceous material is in particulate form having a particle size between about 10 Mesh and about 400 Mesh, and wherein the carbonaceous material is present in an amount of between about 20 mg and about 500 mg.
 11. The cigarette of claim 1, wherein the weight ratio of polyol to polyol ester in the mixture is between about 1:3 and about 25:1.
 12. The cigarette of claim 11, wherein the weight ratio of polyol to polyol ester in the mixture is between about 2:1 and about 10:1.
 13. The cigarette of claim 1, wherein the polyol is present in an amount of between about 1 percent and about 25 percent based on the combined weight of the carbonaceous material and the polyol in the mixture.
 14. The cigarette of claim 13, wherein the polyol is present in an amount of between about 7 percent and about 15 percent based on the combined weight of the carbonaceous material and the polyol in the mixture.
 15. The cigarette of claim 2, wherein the weight ratio of polyol to polyol ester in the mixture is between about 1:3 and about 25:1.
 16. The cigarette of claim 15, wherein the weight ratio of polyol to polyol ester in the mixture is between about 2:1 and about 10:1.
 17. The cigarette of claim 2, wherein the polyol is present in an amount of between about 1 percent and about 25 percent based on the combined weight of the carbonaceous material and the polyol in the mixture.
 18. The cigarette of claim 17, wherein the polyol is present in an amount of between about 1 percent and about 25 percent based on the combined weight of the carbonaceous material and the polyol in the mixture.
 19. A cigarette comprising a filter, wherein the filter comprises a plasticized cellulose acetate tow and a carbonaceous material in particulate form, wherein the carbonaceous material is in contact with an intimate mixture of a polyol ester and a polyol.
 20. The cigarette of claim 19, wherein the weight ratio of polyol to polyol ester in the mixture is between about 2:1 and about 10:1.
 21. The cigarette of claim 19, wherein the polyol is present in an amount of between about 7 percent and about 15 percent based on the combined weight of the carbonaceous material and the polyol in the mixture.
 22. The cigarette of claim 19, wherein the polyol is glycerin or propylene glycol and the polyol ester is triacetin.
 23. The cigarette of claim 19, wherein the plasticizer of the plasticized cellulose acetate tow comprises triacetin.
 24. A method of improving gas phase filtration performance of a carbonaceous material in a smoking article, comprising treating the carbonaceous material with an intimate mixture of a polyol and a polyol ester.
 25. The method of claim 24, wherein the polyol comprises at least one of glycerin and propylene glycol, and the polyol ester comprises a glycerin ester. 